High Doping Concentration and Remarkable Negative Thermal Quenching in Eu 3+ ‐Activated CaCO 3
Jingyi Jing, Zhongliang Li, Xiankai Wang, Xiaoquan Ye, Yanhua Song, Haifeng Zou, Ye ShengABSTRACT
Vaterite CaCO 3 was rapidly synthesized at room temperature via a simple co‐precipitation method without any crystalline phase control agents. High‐concentration Eu 3+ doping induces partial transformation of vaterite into calcite; however, the vaterite‐calcite CaCO 3 can accommodate Eu 3+ dopants at concentrations up to 30 mol% before luminescence quenching. Notably, the CaCO 3 :0.300Eu 3+ phosphor exhibits exceptional thermal stability and a pronounced negative thermal quenching (NTQ) effect. Its emission intensity increases monotonically by a factor of 2.25 over 298–423 K. Simultaneously, it shows outstanding color stability, with a chromaticity coordinates variation (CCV) of merely (0.0098, −0.0081) in this range. Furthermore, a fabricated warm‐white phosphor‐converted LED (pc‐WLED) incorporating CaCO 3 :0.300Eu 3+ achieves a high color rendering index (Ra = 89.7) and a low correlated color temperature (3691 K), demonstrating its potential for high‐power, high‐quality WLED applications.